2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl) acetamide is known as Selexipag. It is developed by Nippon Shinyaku under the brand name of Uptravi®, for the treatment of pulmonary arterial hypertension.
2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl) acetamide was firstly described in U.S. Pat. No. 7,205,302B2 herein after referred as US'302. The said patent also describes its process for the preparation. According to this process the final product was obtained with low yield and purity.
U.S. Pat. No. 8,791,122 (herein after referred as US'122) patent describes crystalline form-I, II and III of 2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl) acetamide. Because of drug compounds having, for example, improved stability, solubility, shelf life and in vivo pharmacology, are consistently sought, there is an ongoing need for new or pure salts, hydrates, solvates and polymorphic forms of existing drug molecules. The novel crystalline forms of 2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl) acetamide described herein help meet this requirement.
US'122 patent describes amorphous form of the compound of formula-1. This patent does not disclose any detailed process for amorphous form and PXRD pattern of amorphous compound of formula-1.
The present invention provides an improved process for the preparation of amorphous form of the compound of formula-1.
The prior art processes described for the preparation of the compound of formula-1 suffer from drawbacks such as more no of steps with low yield and purity. Hence there is a continuous need to develop an improved and novel process for preparation for the compound of formula-1 for commercial manufacturing with high yields and purity.
The present invention describes novel and improved process for the preparation of the compound of formula-1 over the existing processes. The invention also provides novel crystalline forms of the compound of formula-1 and its process for the preparation thereof.